Annotation of src/usr.bin/ssh/kex.c, Revision 1.74
1.74 ! stevesk 1: /* $OpenBSD: kex.c,v 1.73 2006/07/26 02:35:17 stevesk Exp $ */
1.1 markus 2: /*
1.36 markus 3: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.1 markus 4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24: */
25:
26: #include "includes.h"
1.73 stevesk 27:
28: #include <sys/param.h>
1.18 markus 29:
30: #include <openssl/crypto.h>
1.72 stevesk 31:
1.74 ! stevesk 32: #include <stdlib.h>
1.72 stevesk 33: #include <string.h>
1.1 markus 34:
35: #include "ssh2.h"
36: #include "xmalloc.h"
37: #include "buffer.h"
38: #include "bufaux.h"
1.7 markus 39: #include "packet.h"
1.1 markus 40: #include "compat.h"
1.18 markus 41: #include "cipher.h"
1.1 markus 42: #include "kex.h"
1.13 markus 43: #include "key.h"
1.18 markus 44: #include "log.h"
1.21 markus 45: #include "mac.h"
1.23 markus 46: #include "match.h"
1.26 markus 47: #include "dispatch.h"
1.48 provos 48: #include "monitor.h"
1.1 markus 49:
1.7 markus 50: #define KEX_COOKIE_LEN 16
1.48 provos 51:
1.66 djm 52: extern const EVP_MD *evp_ssh_sha256(void);
53:
1.35 itojun 54: /* prototype */
55: static void kex_kexinit_finish(Kex *);
56: static void kex_choose_conf(Kex *);
1.26 markus 57:
58: /* put algorithm proposal into buffer */
1.35 itojun 59: static void
1.26 markus 60: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 61: {
1.61 djm 62: u_int i;
1.26 markus 63:
64: buffer_clear(b);
1.49 markus 65: /*
66: * add a dummy cookie, the cookie will be overwritten by
67: * kex_send_kexinit(), each time a kexinit is set
68: */
69: for (i = 0; i < KEX_COOKIE_LEN; i++)
70: buffer_put_char(b, 0);
1.1 markus 71: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 72: buffer_put_cstring(b, proposal[i]);
73: buffer_put_char(b, 0); /* first_kex_packet_follows */
74: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 75: }
76:
1.26 markus 77: /* parse buffer and return algorithm proposal */
1.35 itojun 78: static char **
1.53 markus 79: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 80: {
1.26 markus 81: Buffer b;
1.7 markus 82: int i;
1.26 markus 83: char **proposal;
1.7 markus 84:
1.70 djm 85: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 86:
1.26 markus 87: buffer_init(&b);
88: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 89: /* skip cookie */
90: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 91: buffer_get_char(&b);
1.7 markus 92: /* extract kex init proposal strings */
93: for (i = 0; i < PROPOSAL_MAX; i++) {
1.26 markus 94: proposal[i] = buffer_get_string(&b,NULL);
95: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 96: }
1.26 markus 97: /* first kex follows / reserved */
98: i = buffer_get_char(&b);
1.53 markus 99: if (first_kex_follows != NULL)
100: *first_kex_follows = i;
1.26 markus 101: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
102: i = buffer_get_int(&b);
103: debug2("kex_parse_kexinit: reserved %d ", i);
104: buffer_free(&b);
105: return proposal;
1.1 markus 106: }
107:
1.35 itojun 108: static void
1.26 markus 109: kex_prop_free(char **proposal)
1.1 markus 110: {
1.61 djm 111: u_int i;
1.26 markus 112:
113: for (i = 0; i < PROPOSAL_MAX; i++)
114: xfree(proposal[i]);
115: xfree(proposal);
1.1 markus 116: }
117:
1.35 itojun 118: static void
1.41 markus 119: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 120: {
1.41 markus 121: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 122: }
1.1 markus 123:
1.35 itojun 124: static void
1.44 markus 125: kex_reset_dispatch(void)
1.29 markus 126: {
1.42 markus 127: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
128: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 129: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 130: }
131:
132: void
1.28 markus 133: kex_finish(Kex *kex)
1.26 markus 134: {
1.44 markus 135: kex_reset_dispatch();
1.28 markus 136:
1.26 markus 137: packet_start(SSH2_MSG_NEWKEYS);
138: packet_send();
139: /* packet_write_wait(); */
140: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 141:
1.52 markus 142: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 143: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 144: packet_check_eom();
1.26 markus 145: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 146:
1.30 markus 147: kex->done = 1;
1.26 markus 148: buffer_clear(&kex->peer);
1.27 markus 149: /* buffer_clear(&kex->my); */
1.26 markus 150: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 151: xfree(kex->name);
152: kex->name = NULL;
1.26 markus 153: }
1.1 markus 154:
1.26 markus 155: void
156: kex_send_kexinit(Kex *kex)
157: {
1.60 avsm 158: u_int32_t rnd = 0;
1.49 markus 159: u_char *cookie;
1.61 djm 160: u_int i;
1.49 markus 161:
1.29 markus 162: if (kex == NULL) {
163: error("kex_send_kexinit: no kex, cannot rekey");
164: return;
165: }
1.28 markus 166: if (kex->flags & KEX_INIT_SENT) {
167: debug("KEX_INIT_SENT");
168: return;
169: }
1.30 markus 170: kex->done = 0;
1.49 markus 171:
172: /* generate a random cookie */
173: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
174: fatal("kex_send_kexinit: kex proposal too short");
175: cookie = buffer_ptr(&kex->my);
176: for (i = 0; i < KEX_COOKIE_LEN; i++) {
177: if (i % 4 == 0)
1.60 avsm 178: rnd = arc4random();
179: cookie[i] = rnd;
180: rnd >>= 8;
1.49 markus 181: }
1.26 markus 182: packet_start(SSH2_MSG_KEXINIT);
183: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
184: packet_send();
185: debug("SSH2_MSG_KEXINIT sent");
186: kex->flags |= KEX_INIT_SENT;
1.1 markus 187: }
188:
1.26 markus 189: void
1.41 markus 190: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 191: {
1.26 markus 192: char *ptr;
1.61 djm 193: u_int i, dlen;
1.26 markus 194: Kex *kex = (Kex *)ctxt;
1.11 provos 195:
1.26 markus 196: debug("SSH2_MSG_KEXINIT received");
1.29 markus 197: if (kex == NULL)
198: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 199:
1.26 markus 200: ptr = packet_get_raw(&dlen);
201: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 202:
203: /* discard packet */
204: for (i = 0; i < KEX_COOKIE_LEN; i++)
205: packet_get_char();
206: for (i = 0; i < PROPOSAL_MAX; i++)
207: xfree(packet_get_string(NULL));
1.51 markus 208: (void) packet_get_char();
209: (void) packet_get_int();
1.39 markus 210: packet_check_eom();
1.19 stevesk 211:
1.26 markus 212: kex_kexinit_finish(kex);
213: }
1.11 provos 214:
1.26 markus 215: Kex *
1.28 markus 216: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 217: {
218: Kex *kex;
1.11 provos 219:
1.70 djm 220: kex = xcalloc(1, sizeof(*kex));
1.26 markus 221: buffer_init(&kex->peer);
222: buffer_init(&kex->my);
223: kex_prop2buf(&kex->my, proposal);
1.30 markus 224: kex->done = 0;
1.26 markus 225:
226: kex_send_kexinit(kex); /* we start */
1.44 markus 227: kex_reset_dispatch();
1.26 markus 228:
229: return kex;
1.11 provos 230: }
231:
1.35 itojun 232: static void
1.26 markus 233: kex_kexinit_finish(Kex *kex)
1.1 markus 234: {
1.26 markus 235: if (!(kex->flags & KEX_INIT_SENT))
236: kex_send_kexinit(kex);
1.1 markus 237:
1.26 markus 238: kex_choose_conf(kex);
1.1 markus 239:
1.54 markus 240: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
241: kex->kex[kex->kex_type] != NULL) {
242: (kex->kex[kex->kex_type])(kex);
243: } else {
1.26 markus 244: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 245: }
246: }
247:
1.35 itojun 248: static void
1.1 markus 249: choose_enc(Enc *enc, char *client, char *server)
250: {
1.23 markus 251: char *name = match_list(client, server, NULL);
1.1 markus 252: if (name == NULL)
253: fatal("no matching cipher found: client %s server %s", client, server);
1.45 markus 254: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 255: fatal("matching cipher is not supported: %s", name);
1.1 markus 256: enc->name = name;
257: enc->enabled = 0;
258: enc->iv = NULL;
259: enc->key = NULL;
1.45 markus 260: enc->key_len = cipher_keylen(enc->cipher);
261: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 262: }
1.69 deraadt 263:
1.35 itojun 264: static void
1.1 markus 265: choose_mac(Mac *mac, char *client, char *server)
266: {
1.23 markus 267: char *name = match_list(client, server, NULL);
1.1 markus 268: if (name == NULL)
269: fatal("no matching mac found: client %s server %s", client, server);
1.21 markus 270: if (mac_init(mac, name) < 0)
1.1 markus 271: fatal("unsupported mac %s", name);
1.21 markus 272: /* truncate the key */
273: if (datafellows & SSH_BUG_HMAC)
274: mac->key_len = 16;
1.1 markus 275: mac->name = name;
276: mac->key = NULL;
277: mac->enabled = 0;
278: }
1.69 deraadt 279:
1.35 itojun 280: static void
1.1 markus 281: choose_comp(Comp *comp, char *client, char *server)
282: {
1.23 markus 283: char *name = match_list(client, server, NULL);
1.1 markus 284: if (name == NULL)
285: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 286: if (strcmp(name, "zlib@openssh.com") == 0) {
287: comp->type = COMP_DELAYED;
288: } else if (strcmp(name, "zlib") == 0) {
289: comp->type = COMP_ZLIB;
1.1 markus 290: } else if (strcmp(name, "none") == 0) {
1.64 markus 291: comp->type = COMP_NONE;
1.1 markus 292: } else {
293: fatal("unsupported comp %s", name);
294: }
295: comp->name = name;
296: }
1.69 deraadt 297:
1.35 itojun 298: static void
1.1 markus 299: choose_kex(Kex *k, char *client, char *server)
300: {
1.23 markus 301: k->name = match_list(client, server, NULL);
1.1 markus 302: if (k->name == NULL)
303: fatal("no kex alg");
1.11 provos 304: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 305: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 306: k->evp_md = EVP_sha1();
1.59 djm 307: } else if (strcmp(k->name, KEX_DH14) == 0) {
308: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 309: k->evp_md = EVP_sha1();
310: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 311: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 312: k->evp_md = EVP_sha1();
1.66 djm 313: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
314: k->kex_type = KEX_DH_GEX_SHA256;
315: k->evp_md = evp_ssh_sha256();
1.11 provos 316: } else
1.1 markus 317: fatal("bad kex alg %s", k->name);
318: }
1.65 djm 319:
1.35 itojun 320: static void
1.1 markus 321: choose_hostkeyalg(Kex *k, char *client, char *server)
322: {
1.23 markus 323: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 324: if (hostkeyalg == NULL)
1.1 markus 325: fatal("no hostkey alg");
1.13 markus 326: k->hostkey_type = key_type_from_name(hostkeyalg);
327: if (k->hostkey_type == KEY_UNSPEC)
328: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 329: xfree(hostkeyalg);
1.1 markus 330: }
331:
1.56 djm 332: static int
1.53 markus 333: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
334: {
335: static int check[] = {
336: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
337: };
338: int *idx;
339: char *p;
340:
341: for (idx = &check[0]; *idx != -1; idx++) {
342: if ((p = strchr(my[*idx], ',')) != NULL)
343: *p = '\0';
344: if ((p = strchr(peer[*idx], ',')) != NULL)
345: *p = '\0';
346: if (strcmp(my[*idx], peer[*idx]) != 0) {
347: debug2("proposal mismatch: my %s peer %s",
348: my[*idx], peer[*idx]);
349: return (0);
350: }
351: }
352: debug2("proposals match");
353: return (1);
354: }
355:
1.35 itojun 356: static void
1.27 markus 357: kex_choose_conf(Kex *kex)
1.1 markus 358: {
1.27 markus 359: Newkeys *newkeys;
1.26 markus 360: char **my, **peer;
361: char **cprop, **sprop;
1.27 markus 362: int nenc, nmac, ncomp;
1.61 djm 363: u_int mode, ctos, need;
1.53 markus 364: int first_kex_follows, type;
1.1 markus 365:
1.53 markus 366: my = kex_buf2prop(&kex->my, NULL);
367: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 368:
1.27 markus 369: if (kex->server) {
1.26 markus 370: cprop=peer;
371: sprop=my;
372: } else {
373: cprop=my;
374: sprop=peer;
375: }
1.1 markus 376:
1.30 markus 377: /* Algorithm Negotiation */
1.1 markus 378: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 379: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 380: kex->newkeys[mode] = newkeys;
1.27 markus 381: ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
1.1 markus 382: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
383: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
384: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 385: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
386: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
387: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 388: debug("kex: %s %s %s %s",
1.1 markus 389: ctos ? "client->server" : "server->client",
1.27 markus 390: newkeys->enc.name,
391: newkeys->mac.name,
392: newkeys->comp.name);
1.1 markus 393: }
1.27 markus 394: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
395: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 396: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
397: need = 0;
398: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 399: newkeys = kex->newkeys[mode];
1.45 markus 400: if (need < newkeys->enc.key_len)
401: need = newkeys->enc.key_len;
402: if (need < newkeys->enc.block_size)
403: need = newkeys->enc.block_size;
1.27 markus 404: if (need < newkeys->mac.key_len)
405: need = newkeys->mac.key_len;
1.1 markus 406: }
1.7 markus 407: /* XXX need runden? */
1.27 markus 408: kex->we_need = need;
1.53 markus 409:
410: /* ignore the next message if the proposals do not match */
1.56 djm 411: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 412: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 413: type = packet_read();
414: debug2("skipping next packet (type %u)", type);
415: }
1.26 markus 416:
417: kex_prop_free(my);
418: kex_prop_free(peer);
419: }
420:
1.35 itojun 421: static u_char *
1.65 djm 422: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
423: BIGNUM *shared_secret)
1.26 markus 424: {
425: Buffer b;
426: EVP_MD_CTX md;
427: char c = id;
1.61 djm 428: u_int have;
1.65 djm 429: int mdsz;
1.61 djm 430: u_char *digest;
1.62 djm 431:
1.65 djm 432: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
433: fatal("bad kex md size %d", mdsz);
1.68 deraadt 434: digest = xmalloc(roundup(need, mdsz));
1.26 markus 435:
436: buffer_init(&b);
437: buffer_put_bignum2(&b, shared_secret);
438:
1.30 markus 439: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 440: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 441: if (!(datafellows & SSH_BUG_DERIVEKEY))
442: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 443: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 444: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 445: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 446: EVP_DigestFinal(&md, digest, NULL);
447:
1.30 markus 448: /*
449: * expand key:
450: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
451: * Key = K1 || K2 || ... || Kn
452: */
1.26 markus 453: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 454: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 455: if (!(datafellows & SSH_BUG_DERIVEKEY))
456: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 457: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 458: EVP_DigestUpdate(&md, digest, have);
459: EVP_DigestFinal(&md, digest + have, NULL);
460: }
461: buffer_free(&b);
462: #ifdef DEBUG_KEX
463: fprintf(stderr, "key '%c'== ", c);
464: dump_digest("key", digest, need);
465: #endif
466: return digest;
1.1 markus 467: }
468:
1.30 markus 469: Newkeys *current_keys[MODE_MAX];
1.27 markus 470:
1.23 markus 471: #define NKEYS 6
1.26 markus 472: void
1.65 djm 473: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 474: {
1.15 markus 475: u_char *keys[NKEYS];
1.61 djm 476: u_int i, mode, ctos;
1.1 markus 477:
1.65 djm 478: for (i = 0; i < NKEYS; i++) {
479: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
480: shared_secret);
481: }
1.1 markus 482:
1.52 markus 483: debug2("kex_derive_keys");
1.1 markus 484: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 485: current_keys[mode] = kex->newkeys[mode];
486: kex->newkeys[mode] = NULL;
1.69 deraadt 487: ctos = (!kex->server && mode == MODE_OUT) ||
488: (kex->server && mode == MODE_IN);
1.30 markus 489: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
490: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
491: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 492: }
1.27 markus 493: }
494:
495: Newkeys *
496: kex_get_newkeys(int mode)
497: {
1.30 markus 498: Newkeys *ret;
499:
500: ret = current_keys[mode];
501: current_keys[mode] = NULL;
502: return ret;
1.57 djm 503: }
504:
505: void
506: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
507: u_int8_t cookie[8], u_int8_t id[16])
508: {
509: const EVP_MD *evp_md = EVP_md5();
510: EVP_MD_CTX md;
511: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
512: int len;
513:
514: EVP_DigestInit(&md, evp_md);
515:
516: len = BN_num_bytes(host_modulus);
1.61 djm 517: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 518: fatal("%s: bad host modulus (len %d)", __func__, len);
519: BN_bn2bin(host_modulus, nbuf);
520: EVP_DigestUpdate(&md, nbuf, len);
521:
522: len = BN_num_bytes(server_modulus);
1.61 djm 523: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 524: fatal("%s: bad server modulus (len %d)", __func__, len);
525: BN_bn2bin(server_modulus, nbuf);
526: EVP_DigestUpdate(&md, nbuf, len);
527:
528: EVP_DigestUpdate(&md, cookie, 8);
529:
1.58 djm 530: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 531: memcpy(id, obuf, 16);
532:
533: memset(nbuf, 0, sizeof(nbuf));
534: memset(obuf, 0, sizeof(obuf));
535: memset(&md, 0, sizeof(md));
1.1 markus 536: }
1.26 markus 537:
538: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
539: void
540: dump_digest(char *msg, u_char *digest, int len)
541: {
1.61 djm 542: u_int i;
1.26 markus 543:
544: fprintf(stderr, "%s\n", msg);
1.37 deraadt 545: for (i = 0; i< len; i++) {
1.26 markus 546: fprintf(stderr, "%02x", digest[i]);
547: if (i%32 == 31)
548: fprintf(stderr, "\n");
549: else if (i%8 == 7)
550: fprintf(stderr, " ");
551: }
552: fprintf(stderr, "\n");
553: }
554: #endif
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